test: move timing-sensitive test to sequential

test-https-server-keep-alive-timeout relies on server timeouts and
whatnot that will be inherently unreliable on a busy host. The test
fails when run with a high `-j` value and higher `--repeat` value passed
to `tools/test.py`. Move the test to `sequential`.

PR-URL: https://github.com/nodejs/node/pull/16775
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/sequential/test-https-server-keep-alive-timeout.js

@@ -0,0 +1,79 @@
+'use strict';
+
+const common = require('../common');
+
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+
+const fixtures = require('../common/fixtures');
+const https = require('https');
+const tls = require('tls');
+
+const tests = [];
+
+const serverOptions = {
+  key: fixtures.readKey('agent1-key.pem'),
+  cert: fixtures.readKey('agent1-cert.pem')
+};
+
+function test(fn) {
+  if (!tests.length) {
+    process.nextTick(run);
+  }
+  tests.push(fn);
+}
+
+function run() {
+  const fn = tests.shift();
+  if (fn) fn(run);
+}
+
+test(function serverKeepAliveTimeoutWithPipeline(cb) {
+  const server = https.createServer(
+    serverOptions,
+    common.mustCall((req, res) => {
+      res.end();
+    }, 3));
+  server.setTimeout(500, common.mustCall((socket) => {
+    // End this test and call `run()` for the next test (if any).
+    socket.destroy();
+    server.close();
+    cb();
+  }));
+  server.keepAliveTimeout = 50;
+  server.listen(0, common.mustCall(() => {
+    const options = {
+      port: server.address().port,
+      allowHalfOpen: true,
+      rejectUnauthorized: false
+    };
+    const c = tls.connect(options, () => {
+      c.write('GET /1 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      c.write('GET /2 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      c.write('GET /3 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+    });
+  }));
+});
+
+test(function serverNoEndKeepAliveTimeoutWithPipeline(cb) {
+  const server = https.createServer(serverOptions, common.mustCall(3));
+  server.setTimeout(500, common.mustCall((socket) => {
+    // End this test and call `run()` for the next test (if any).
+    socket.destroy();
+    server.close();
+    cb();
+  }));
+  server.keepAliveTimeout = 50;
+  server.listen(0, common.mustCall(() => {
+    const options = {
+      port: server.address().port,
+      allowHalfOpen: true,
+      rejectUnauthorized: false
+    };
+    const c = tls.connect(options, () => {
+      c.write('GET /1 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      c.write('GET /2 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+      c.write('GET /3 HTTP/1.1\r\nHost: localhost\r\n\r\n');
+    });
+  }));
+});